Electric heating unit



Feb. 23 1926. 1,574,308

E. A. RUTENBER ELECTRIC HEATING UNIT Filed August 22, 1924 2 eets-Sheet 1 awwemtoz W CLW Feb. 23 1926. 1,574,308

E. A. RUTENBER ELECTRIC HEATING UNIT Filed August 22 I 2 Sheets-Sheet 2 noemlioz MCLWL Patented Feb. 23, 1926.

EDWIN A. BUTENIBER, OF MILWAUKEE, WISCONSIN.

nnncrnrc HEATING UNIT.

Application filed August 22, 1924. Serial No. 783,514.

To all whom it may concern:

Be it known that I, EDWIN A. RUTENBER, a citizen of the United States, and a resident of the city of Milwaukee, in the county of Milwaukee, State of Wisconsin, have invented certain new and useful Improvements in Electric Heating Units, of which the following is a specification.

The improvements relate to electric heat ing units employing a resistance element supported partly and surrounded by a body of non-conducting material, and their ob jects are, among others, to render the said unit andits connections stronger, more durable and efiicient and easier to install in or remove from the stove or other device in which it is mounted,-and to these ends to provide the unit with a reinforcing and protecting outer shell or casing; to provide for drainage of liquids which may be spilled thereon and for an upward circulation of air therethrough; to cause the upward radiation of heat and prevent the loss of heat through radiation in other directions; to provide a strong, rigid and effective connecting device for the unit and the wires which supply current thereto and a strong and rigid connection between such device and the unit, and also to facilitate the assemblage with and replacement in the shell of the non-conducting holder for the resistance element.

Other objects and advantageswill be apparent to those familiar with devices of the character to which the improvements relate.

The improvements are illustrated in the accompanying drawings, referred to herein,

- in which is illustrated an embodiment comprising an outer metallic shell for the heat unit in the form of a deep dish having an annular ledge above its bottom upon which the grooved plate or brick of non-conductive material is supported and having securely bolted to its bottom an insulator block with connecting terminals rigidly mounted therein and connected with the resistance wires in the grooves, the said metallic shell also having a central upwardly extending hollow boss to receive the central connecting screw of the wire supporting plate and support and hold the plate centrally, and apertures between its center and sides communicating with the space in the bottom thereof and located beneath the holes of the plate to form air and drainage channels.' The shell also has an upper outwardly turned annular flange for supporting the entire device in the hole of a stove top or the like.

In the said drawings, Fig. 1 is a side elevation of an electric heatingunit embodying the improvements; Fig. 2 is an inside view; F ig. 3 is an elevation of the connecting terminals; Fig. 4L is a plan of the insulating holder and resistance wires of the unit; Fig. 5 is a vertical section on the line 55 of Fig. a; and Fig. 6 is a vertical section on the line 66 of Fig. 2.

The outer metallic shell is in the shape of a shallow bowl and comprises an upper part 1 with outwardly extending flange 2 and lower part 3 of the less diameter,an annular step or shoulder 4 being formed where the two parts of the bowl join, an upwardly extending hollow central boss 5 and a vertical flange or key 6. The annular horizontal ,fiange 2 provides a support for the unit in a stove top opening, and the flange 6 provides a key to prevent rotation, while the boss 5 with its central threaded aperture 7 aifords a means for connecting the supporting member of insulating material 8 at that point.

This insulating support for the resistance wires has continuous grooves 9 and 10 formed therein, for the reception of the resistance wires, and at the bends of these grooves overhanging portions 11 extend over the wires, and apertures 12 extend through to the bottom of the insulator communicating with the space 13 in the bottom of the shell. The insulating holder 8 is supported at its edges on the shoulder at andcentrally on the boss 5, and has a central aperture 14 through which a screw bolt may be passed into the threaded aperture 7 of the boss.

I The block 15 for mounting the connecting terminals and conductor wires 20 for connecting them with the resistance wires is secured to the bottom of the shell by threaded shanks 16 extending from the terminal connections 17 and passing through the block and shell bottom and secured by means of a nut 18. Binding posts 19 connect the wires 20 with the terminal connection, extending through the studs 21 of the block 15, which are passed through openings in the bottom of the outer shell. As the block 15 is made of insulating material, and an insulating washer 22 and sleeve 23 are interposed between the shank 16 and the shell,

the terminal members 17 and the wires from from the metal shell.

The sturdy and substantial mounting block 15 for the connector terminals 17 which is thus provided, insures that the terminals are retained in their fixed positions in alinement with sockets, not shown, formed to receive the terminals when the device is set in position in a stove-top opening. The rigid seating of the terminals prevents displacement or loosening thereof by careless handling of the heating unit shell and the substantial size of the insulating block 15 provides an ample margin of safety against short-circuiting of the current through the terminals without traversing the heating coils 24 and 25 positioned in the grooves 9 and 10 of the insulating support 8.

Preferably the two separate and distinct heating coil members 24 and 25 are used to provide various heating effects, either coil being used alone or both coils being used together, as will be understood. The coils 24 and 25 are supplied with different resistance Values for this purpose.

The apertures or passages 12 in the body of the coil insulating and supporting member 8, which have already been referred to, are preferably relatively numerous, an aperture being provided at a considerable number or all of the bends in the coil-receiving grooves in order to quickly vent or dispose of liquids finding their way into the grooves as a result of accidental spilling, boiling over, or the like. By thus rapidly disposing of the liquid, local short-circuiting effects on the heating coils are obviated with the result that the full efficiency of the coils is maintained.

A further feature of construction utilized in the draining of spilled liquids from the device resides in the provision of drainage openings 26 in the lower wall 3 of the shell supporting the insulating plate 8. The drainage openings 26 in the shell are arranged to underlie certain of the apertures 12 extend ing through the coil insulating support 8. With this arrangement it will be seen that liquid drained through the apertures 12 also finds its way through the openings 26 and out of the shell.

Another function of the superposed openings in the insulating plate 8 and the supporting shell therefor is to provide a passage through which an upward flow of air may take place to assist in the upward propagation of heat currents against the vessel in position on the heating unit. Thus not only is heat directed upwardly to be usefully employed but the radiation of heat downwardly to be wastefully dissipated. The

conservation of heat is still further brought about by the chamber or insulating air space 27 formed between the bottom of the plate 8 and the lower wall 3 of t shell.

Reference has already been made to the complementary construction of the plate 8 and its supporting shell and it will be seen that the coilsupporting plate is readily seated in the shell and fastened in place through the use of a single screw member so that the assembly operation is quickly and economically efi'ected.

In order to prevent angular displacement of the insulating disk 8 within the shell such as might disrupt the circuit connections, a lug 28 on the shell is provided for registration with a notch provided for the purpose in the edge of the plate 8.

What I claim is 1. In an electric heating device, a shallow shell member having a shoulder formed on the inner side walls and a lug struck up from the bottom thereof, a support of insulating material for a heating element resting directly on said shoulder and said lug, and said support being attached to said lug.

2. In an electric heating device, a shallow dish-shaped shell member having a shoulder formed on the inner side walls and an inverted cup-shaped lug struck up from the bottom thereof, an insulating support for a heating element resting on said shoulder and said lug to provide an air space between the bottom of the support and the bottom of the shell member, and said support being attached to said shell member only at its point of engagement with said lug.

3. In an electric heating device, a shallow dish-shaped shell member having a shoulder formed along the inner surface of the side walls thereof, an inverted cupshaped lug struck up from the bottom of said shell, a disk-shaped insulating support for a heating element arranged to rest on said shoulder and said lug to provide an air chamber beneath the support, screw fastening means for attaching said support to said lug, grooves in the outer face of the support for receiving a heating element, and ports extending through the support to provide passageways for ascending air currents.

4:- In an electric heating device, a shallow dish-shaped shell member having a shoulder formed along the inner surface of the side walls thereof, an inverted cup-shaped lug struck up from the bottom of said shell, a disk-shaped insulating support for a heating element arranged to rest on said shoulder and said lug to provide a chamber beneath said support, grooves in the upper face of said disk for receiving a heating element, and drainage ports extending from said channels into said chamber.

5. In an electric heating device, a. shale supporting low dish-shaped shell member having a shoulder formed along the inner surface of the side walls thereof, an inverted cupshaped lug struck u from a central portion of the bottom of t e shell, and a disk-shaped insulating support for a heating element arranged to rest on said shoulder and said lug.

6. In an electric heating device, a shallow dish-shaped shell member having a shoulder formed along the inner surface of the side walls thereof, an inverted cupshaped lug struck up from a central, portion of the bottom of the shell, a disk-shaped insulating support for a heating elemert resting on said shoulder and said lug, perfo'rations in said support, and perforations in the bottom of said shell beneath the perforations in the sup ort.

7. In an electric eating device, a shal low dish-shaped shell member having a shoulder formed along the inner surface of the side walls thereof, an inverted cupup from a central porshaped lug struck tion of the bottom of the shell, a disk-shaped insulating support for a heating element resting on said shoulder and lug and attached to said lug, a chamber beneath said support, said support being provided with grooves in its upper surface for holding a heating element, ports leading from said grooves to said chamber, and the bottom of said shell being provided with ports underlying the ports in said insulating support.

8. In an electric heating device, a shallow dish-shaped metallic shell member having a shoulder formed along the inner wall to support an insulating support for a heating element in a spaced apart relation with the'bottom of the shell, and a block of inbers projecting connected therewith and a block of insulatsulating material of relatively massive roportions mounted on the bottom of the s ell member to support connector terminals.

9. In an electric heating device, a rigid metallic shell member, an insulating support for a heating member thereon, contact memfrom said shell and rigidly ing material of relatively massive proportions between said projecting contact members and the shell, and means for rigidly securing said block and members in their relative positions and to the shell.

10. In an electric heating device, a rigid metallic shell member, an insulating support supported therein and secured thereto. contact members projecting beyond the shell, a block of insulating material adjacent thereto and extending through the shell, and means for securing said contact members and block to the shell, the said elements forming a rigid unitary element.

11. In an electric heating device, a rigid shell member, an insulating support mount-- ed therein and above the bottom thereof, contact members extending from the shell, a block of insulating material in proximity to the contact members mounted on said shell and extending therethrough, said block having passages therein for connecting wires, binding members on the contact devices for said wires, and a removable connection unitirtilg lsaid block and contact members and the s e1 Witness my hand this 7th day of August, 1924, at the city of Milwaukee, in the county of Milwaukee, State of Wisconsin.

EDWIN A. RUTENBER. 

